Boston Marathon bombing suspect apprehended

The suspect in the Boston Marathon bombings was apprehended on Friday after being found hiding in a boat in a homeowner's backyard.

Police exchanged gunfire with Dzhokhar Tsarnaev, 19, after tracking him down in Watertown, a suburb of Boston. He was found less than an hour after authorities lifted a city-wide order for residents to stay indoors.

Authorities captured the suspect after a resident of Franklin Street, who came out of his home after the lockdown was lifted, noticed blood near the boat. The suspect had escaped earlier in the day after a police shootout claimed the life of his elder brother, Tamerlan, believed to be an accomplice.

Three people lost their lives and more than 170 were injured when two bombs exploded near the finish line on Monday.

The brothers were captured on security footage on the sidewalk before the blast. The pair were the sons of Chechen refugees from the Caucasus region of southern Russia. The family is thought to have moved to the U.S. in 2001 from the Russian republic of Dagestan. Dzhokhar was awarded a scholarship to pursue further education. According to his father, he wanted to become a brain surgeon.

Tamerlan, 26, was an amateur boxer and described himself as a "very religious" non-drinker and non-smoker.

According to officials, the FBI interviewed Tamerlan in 2011 after a request from a foreign government, believed to be Russia. However, agents closed the case after finding no cause for concern.

Speaking at a night press conference, US President Barack Obama pledged to find out what had motivated the bombers.